From ancient times audible signals were used to indicating the passage of time, varying from ship bells every half an hour through the classic mechanical grandfather clock to today's digital watches that indicate a full hour with a short sound. Therefor, the activation of an audio signal at given times is well known. However that same tone is in many cases distinct and distracting. Bells or electronic alarms command attention by their nature. And while the need to command attention was imminent in times past, today, with the ready availability of time sources, commanding attention is not required in many instances. However the esthetically pleasing effects of regular indication of passage of time is still desired by many.
Electrical and mechanical clocks capable of producing an electrical signal, either a pulse or a switch closure, at every hour or half-hour are readily available. Common electrical design principles make it obvious to create a clock that will generate a number of pulses every hour, commensurate with the number of hours, i.e. one pulse for one o'clock, two pulses for two o'clock, etc.
Wind chimes have been used for centuries for their pleasing musical effects. Unlike gongs and bells they seem to allow continuous sound that is clearly audible but that does not distract people from daily activities. Chimes operate frequently at night without disturbing sleep of nearby persons, as compared to the jarring effect of a bell or an electronic alarm. U.S. Pat. No. 5,208,578, Tury et al. teaches a solar powered chime, operated by a mechanical striker in a random fashion to simulate a wind chime indoors.